School of Physics Lecture Demonstration Manual

Wa-2 Phase and Group Velocity

Published: Tuesday 14 March 2006 - Updated: Wednesday 30 March 2011

Aim

To demonstrate the difference between phase and group velocity.

Apparatus

Diagrams

Click on pictures to enlarge.

Phase n Group Velocity Diagram 2

Phase n Group Velocity Diagram 1

Description

Two signal generators are connected to separate channel inputs on the four channel C.R.O. The third channel contains the sum of the two signals via the isolating resistors. If the two frequencies of the oscillators are approximately equal the resulting waveforms adequately demonstrate the phase and group velocity of the packet.

Safety notes

Electrical safety 

Maintenance 

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